Printing mechanism



March 31, 1959 YR. 5. MARK 2,879,712

' 4 PRINTING MECHANISM Filed July 16, 1957 United States Patent PRINTING MECHANISM Richard S. Mark, Arcadia, Califi, asslgnor to 'Clary Corporation, San Gabriel, Calif., a corporation of California Application July 16, 1957, Serial No. 672,315

4 Claims. (Cl. 101-95) This invention relates to printing mechanisms for calculating machines and the like and has particular reference to printing mechanisms involving rotary type wheels which are moved into and out of printing contact with the paper.

In mechanisms of the above type, the type wheels, are, in general, normally entrained with the drive elements therefore so as to be set to print the proper digital values, but during the printing phase of a machine cycle, the type wheels are detrained from such drive elements and are moved toward the paper. Thereafter, they are returned into entrainment with the drive elements.

As the speeds of printing mechanisms of this type are increased, considerable difficulty is encountered in obtaining proper printing action and in preventing the printing wheels from going out of time with their drivers as they are detrained and later reentrained.

It therefore becomes a principal object of the present invention to provide a printing mechanism embodying type wheels movable into and out of contact with the paper which are capable of operating at high speeds.

Another object is to provide a printing mechanism of the above type in which a uniform printing impression is obtained from all type wheels.

A further object is to provide a printing mechanism of the above type in which there is no tendency for the type wheels to go out of time with their drivers during a printing operation.

The manner in which the above and other objects of the present invention are accomplished will be readily understood on reference to the following specification when read in conjunction with the accompanying drawings, wherein:

Fig. 1 is a sectional elevation view illustrating a part of an adding-listing machine and printing mechanism embodying a preferred form of the present invention, and illustrating the mechanism in full cycle position.

series of denominationally arranged racks 11 which may be differentially advanced to different numerical positions during each machine cycle under control of settable amount keys (not shown).

The machine is motor driven through a shaft 12 which revolves one revolution in a counterclockwise direction during each cycle. I

The printer comprises a series of type or printing wheels 13 equal in number to the number of racks 11. Each wheel has thereon a series of type characters ranging progressively in value from 0 to 9 and these wheels are so entrained with associated racks that each will print a character corresponding to the numerical position to which the rack is moved.

Each type wheel is rotatably mounted on a separate two part arm 14 which is pivotally mounted on a support shaft 15 and is spring urged clockwise by a tension spring 16 extending between the arm and a suitable portion of the machine frame (not shown). Each wheel 13 has a gear 17 integral therewith and meshing with a gear 18 also rotatably mounted on the associated arm 14.

The various arms 14 are spaced from eachother by hubs 19, each attached to a respective one of the hubs.

Normally, except during printing operations, the arms are held in their normal positions illustrated in Figs. 1, 2 and 3, and when in such positions, the gears 18 are meshed with aligned idler gears 20 rotatably mounted on a support shaft 121. The latter idler gears are continuously meshed with their respective racks 11.

Describing now the means for holding the various arms 14 in position to mesh the gears 18 with idlers 20 andfor releasing the same for printing operation, a printing control bail 21 is provided, the arms of which are pivotally supported by the shaft 15. The bail 21 comprises a cross piece 22 engageable with lugs 23 on the various printer arms 14. The cross piece is provided with combing teeth 25 (Fig. 5) which extend forwardly to normally properly space the upper portions of the arms 14, and accordingly, the type wheels 13. The bail 21 is urged clockwise by a tension spring to hold a roller 25 mounted on an extension on one of the legs thereof against a two part lever 26. The latter is fulcrumed on a support shaft 27 and is provided with a cam follower roller 28 which rides on the periphery of a printercontrol cam 30 keyed on the drive shaft 12.

At the printing point in'the cycle, the roller 28 drops into a depression in the cam 30, allowing the spring 50 to Fig. 2 is a sectional view similar to Fig. 1, but illustrati ing the mechanism partially through a cycle and preparatory to a printing operation.

Fig. 3 is a sectional view similar to that of Fig. 2, but illustrating the printing control bail and mechanism for controlling the same.

Fig. 4 is a sectional view illustrating the printing mechanism in a printing operation.

Fig. 5 is a fragmentary plan view illustrating the printing control bail and is taken along line 5--5 of Fig. 3.

The present invention is disclosed in connection with the well-known Clary adding machine which is generally disclosed in the R. E. Boyden Patent No. 2,583,810, issued on January 29, 1952. Reference may be had to the Boyden patent for an understanding of details of the machine not specifically disclosed herein. Accordingly, various controls. and operating mechanism of themachine are omitted herein forthe sake of brevity and clarity since they are not deemed necessary for an understanding of the present invention.

rock the bail 21 clockwise, permitting the individual springs 16 to also rock the arms 14 to efiect a printing impression of the type wheels 13 against the paper (not shown) supported by a platen 29. Since the combing teeth 24 move with those type arms which are otherwise allowed to so move, any binding or frictional tendencies existing between the arms and combing teeth will not adversely aflect uniformity of printing impression between the type wheels, but, on the other hand, will tend to make such impression more uniform.

The machine is of the rack driven type comprising a It will be noted that the combing teeth 24 are pointed at their outer ends to enable proper aligning of all arms 14 when the bail is returned after the printing operation.

Describing now the means for detenting the type wheels and idlers 20 during the printing operation in which the type wheels 13 move toward the platen and the racks 11 are held in whichever position they have been adjusted to, each arm 14 has pivoted thereto at 31, a detent 32 in the form of a bell crank. A tension spring 33 extending be tween each detent and its arm 14 urges the detent counterclockwise toward a position in which a detenting tooth 51 thereon will engage between two teeth on the gear 17.

A detenting bail 34 is pivoted on a support rod 35 and is provided with a bail rod 36 located over the tails of the various dctents 32. The .lowercndofthe bail 34 is formed into an aligner section 37 adapted to engage between two of the teeth on each of the idler gears 20.

One end of a link 38 is connected by an eccentrically adjustable pivot 39 to the lower end of the bail 34 and the other end of the link is connected by .a pin and slot coupling 40 to a cam follower 41. The mid-portion of the link is provided with a slot 42 for a slideable support upon the shaft 121. The cam follower 41 is fulcrumed upon the shaft 27 and is provided at the lower end thereof with two rollers '43 and 44, engaging, respectively, the peripheries of complementary formed cams 4S and 46 keyed on shaft 12.

The timing relationship between cams 45, 46 and 30 is such that the detent bail 34 is rocked counterclockwise from its position shown in Fig. 1 to simultaneously engage detent teeth 51 and aligner section 37 shortly before the printer control bail 21 is rocked under control of cam 30 to release type wheel support arms for movement toward the platen. Thus, definite assurance is given that the type wheels are properly detented before they become detrained from the idlers 20.

Likewise, the relationship between the cams is such that the bail 34 will release the detent teeth 51 and aligner section 37 only after the gears 18 have fully meshed with the idlers 20.

It will be noted that upon return of the arms 14 to their normal positions by the cam 30, projections 62 thereon strikes a cross rod 63 to thereby limit the arms against overthrow tendencies. Also, it should be noted for a purpose hereinafter described, that the curved portions 47 of the detents 32 and arms 14 pass below the bail rod 36 with very little clearance as the arms 14 are swung toward the platen.

As described in detail in the above Boyden patent, zero suppressing latches 49 are provided adjacent the arms 14 to suppress printing of zeros to the left of the highermost significant digit printed. For this purpose, the latches are pivotally supported on a rod 52 extending through arcuate' slots 53 in the idler gears 20. Ears 54 on the latches are adapted to be positioned over hooks 55 formed on the arms 14 to prevent movement of the latter toward the platen.

The slot 53 of each idler has a recessed portion 56 which, when the associated printer wheel is set to print 0, is directly adjacent a tab 57 on the associated latch 49, permitting the latch when otherwise allowed to do so, to be swung clockwise sufiiciently to place its car 54 over the hook 55. However, when the idler is rotated to any numerical position other than 0, the raised arcuate edge 58 of the slot 53 therein-will be positioned under the tab 57 thus preventing the associated latch '49 from blocking movement of its associated type wheel arm 14 toward the platen.

Overlapping ears (not shown) on the various latches 49 enable any one latch, when held in its outer position (shown in Fig. 3), to hold all lower denomination latches to the right thereof in arm releasing positions.

The various latches 49 are normally held in their arm releasing positions by a bail rod 60 mounted between the legs of the bail 34. The latter rod extends through triangular shaped openings 61 in the various latches and normally engages the left hand edges of such openings. When the bail 34 is rocked counterclockwise shortly before the printing operation is effected, the bail rod 60 recedes from the forward edges of the openings 61 in the latches 49, permitting the latter to be either held in arm releasing positions by the arcuate edges 58 of the respective idlers or to move into arm latching positions in those orders to the left of an order containing the highermost significant digit printed.

An important feature of the invention is the arrangement whereby the printer will be prevented from operating in the remote event that the aligner 37 should engage the tip of a tooth on any of the idler gears 20. In this event, the bail 34v will be permitted to rock only partially through its stroke and the cam follower 41 will thereafter yield as the cycle continues. Accordingly, the bail rod 36 will be located in a position intermediate its positions illustrated in Figs. 1 and 2, whereupon the curved portions 47 of the detents 32 will strike the bail rod, blocking all of the arms 14 from moving toward the platen. Thus, absence of a printed line will readily indicate that one of the type wheels was not properly registered in printing position.

Although I have described my invention in detail and have therefore used certain terms and languages herein, it is to be understood that the present disclosure is illustrative rather than restrictive and that changes and modifications may be made without departing from the spirit or scope of the invention as set forth in the claims appended hereto.

Having thus described my invention, what I desire to secure by United States Letters Patent is:

1. In a calculating machine, a printing mechanism comprising a platen, a plurality of printing wheels having type characters on the peripheries thereof, yieldable means for moving said wheels toward said platen, means for rotating said wheels to ditferent printing positions, detents for said wheels, spring means for urging said detents toward detenting engagement with said wheels, a detent bail for normally holding said detents out of detenting engagement, and means for moving said detent bail from its holding position to a position in which said detents en gage said wheels, said bail being effective when out of said last mentioned position to prevent movement of said wheels toward said platen.

2. In a calculating machine, a printing mechanism comprising a platen, a plurality of printing wheels having type characters on the peripheries thereof, movable arms for pivotally supporting said wheels, yieldable means for moving said arms and wheels toward said platen, means for rotating said wheels to different printing positions, detents carried by said arms for detenting said wheels, spring means for urging said detents into detenting positions, a detent bail for holding said detents out of detenting positions, and means for moving said detent bail from its holding position to a position in which said detents engage said wheels, said detent bail being efiective when in its holding position to prevent movement of said wheel toward said platen.

3. In a calculating machine, a printing mechanism comprising a platen, a plurality of print wheels having type characters on the peripheries thereof, means for rotating said wheels to different positions, means for moving said wheels toward said platen, detents for detenting said wheels, a detent control element, said control element being movable to one position to simultaneously release said detents from said wheels and to release said rotating means, said control element being movable to a second position to simultaneously enable said detents to detent said wheel and to detent said rotating means.

4. In a calculating machine, a printing mechanism comprising a platen, a plurality of printing wheels having type characters on the peripheries thereof, arms pivotally supporting said wheels for movement toward said platen, drive elements for rotating said wheels to different positions, detents carried by said arms for detenting said wheels, spring means urging said detents toward detenting engagement with said wheels, a detent control element, said control element being movable to one position to simultaneously release said detents from said wheels and to release said rotating means, said control element being movable to a second position to permit movement of said detents by said spring means and for detenting said rotating means.

Mehan May 5, 1942 Keuper Ian. 22, 1952 

